UIImageView and scale to fill not work when downloading image from web

I guess I'm missing somthing here.

I have custom uitable开发者_StackOverflow社区viewcell with xib and uiimageview in it.

The UIImageView mode is scale to fill.

For testing I set image in interface builder, just to see if the image is scale to fill and it is.

When the app runs, it download image from web server and set it to the uiimageview.image of the cell.

If the image size is less then the uiimageview frame, the image is not scale to fill.

Why is that ? and what I need to do, so every image i download will resize to the imageview frame.

So frustrating.

Thanks in advance.